Monday 14 September 2009 16.03 EDT
First published on Monday 14 September 2009 16.03 EDT

This was not, Kim Clijsters acknowledged with some understatement, the plan. When the Belgian agreed to play an exhibition match at Wimbledon in May, she was two years out of the game, having been forced by injury to retire at 23, when most people are barely starting their first job. Her daughter, Jada, was just over a year old and she had no intention of returning to competitive tennis, though having begun practising again, she thought she may as well compete in a couple of tournaments that had offered her wildcard entries.

On Sunday, in one of the most remarkable sporting comebacks in recent times, Clijsters won the US Open, posing for photographs with the heavy silver cup in one hand and Jada, now 18 months, perched on the opposite hip. The player and her partner, the American basketball player Brian Lynch, had moved the toddler's nap time to allow her to stay up late enough to watch Clijsters, now 26, become the first mother to win a tennis Grand Slam since 1980. As Evonne Goolagong Cawley, the last person to do so, put it yesterday: "Go moms!"

While the simple fact that Clijsters is a mother may not be the most remarkable thing about her victory – the Open, astonishingly, was only the third tournament she has entered since her return – the player herself seemed to consider it so as she struggled to take in her giddy return from domestic anonymity to sporting stardom.

"As a woman, I came to a stage in my life, too, where I wanted to get married," she told reporters. "We wanted to start a family, and I was glad. I feel very lucky that I got this chance to be back here now and that I made that decision, because it's obviously been a good choice. Being a mother is obviously my first priority and being a wife … I'm just very lucky that I'm able to combine both and that my family supports me in doing this."

Clijsters is far from the first sportswoman to excel after having a child – Paula Radcliffe won the New York marathon in 2007 10 months after having a child, the Kenyan runner Catherine Ndereba broke the world records at 5k and 15k in 1998 a year after giving birth, and last month, the golfer Catriona Matthew won the British Open when her second daughter was just 10 weeks old.

But success in tennis has broadly eluded mothers, a comparative paucity perhaps explained by the punishing tournament schedule that requires players to travel the globe amassing points to qualify for the major championships. Asked for her immediate plans, Clijsters said: "It is the greatest feeling in the world being a mother and I just can't wait to spend the next few weeks with [Jana] back in routine schedule with her at home again."

Roger Federer is a proud new father of twins, but it would seem more of a surprise if he were to announce a few weeks off. There is plenty of data to back up an apparent gender disparity outside the narrow field of tennis. In Britain, for example, there remains a deeply ingrained divide between the working patterns of mothers and fathers. According to an Equality and Human Rights Commission report earlier this year, 36% of the former work part-time, while fathers are most likely to work 40-49 hours a week. While more than two-thirds (68%) of working-age women are in employment, according to the Office for National Statistics, for those with under-fives that figure drops to 57%. The same study found that the age of a man's children has no impact on his likelihood of being in work. Only 4% of men with dependent children work part-time.

While their own returns to work may not have been quite so precipitous, working mothers yesterday said they recognised some aspects of Clijsters's situation, most notably perhaps her own and others' surprise that she should excel once again having given birth comparatively recently.

"People definitely have much lower expectations of you when you go back after having a baby," says Naomi Thompson, 31, a charity campaigner from Belfast who has three children aged three, two and four months. Though she returned to work full-time after her first two children, eager to perform at the same level as before, she said: "I think they just assumed that I would just produce less work for myself, and work to a lesser level. Some people might see that as an advantage, but I resented that a bit. I was interested in my job and I wanted to do it well. I didn't want my identity to be completely changed: now you're a mum, that's your career."

Lizzie Bishop, 33, a statistical analyst from London, accepted voluntary redundancy while on maternity leave after her employer questioned how ambitious she would be after having her first child, now 14 months. "I think if you are a woman and have family responsibilities, without question you are viewed differently," she says. "There was an immediate assumption that I would have a different attitude to my work because I was a woman and had a child. Whereas there is absolutely no reason why, being a mother, you can't excel."

She has escaped negative expectations since starting to work on a consultancy basis with new employers who know she is a mother, but deal with her as a professional. Clijsters, similarly, prefers to refer to her latest tennis successes as a "second career" rather than a comeback, arguing that comparisons with her younger self are irrelevant.

But the feminist writer Natasha Walter, who recently gave birth to her second child, cautions against attempting to extrapolate from Clijsters's remarkable tale to the experiences of ordinary women. "The last thing we want is for one woman's experience of keeping all the balls in the air to be turned into a model into which we expect all women to fit. But the fact that we are so interested in how quickly after giving birth a woman goes to a political meeting or wins a tennis tournament does show us how difficult these issues still are. There is a constant sense that this should mean something for all women after childbirth, whereas in fact everyone is an individual and we all react to motherhood in a different way."

Julia Hobsbawm – the businesswoman and mother of three who has written a book, The See-Saw, about balancing work and family – argues that there are many variables that determine whether a woman, after a pregnancy, finds herself in a position where she is able to return to competing at a high level. "I think there is a huge spectrum of resilience rates among women and their families. Some women really do fall apart with lack of sleep, I am one of them, whereas other people just manage it. I think you cannot prescribe a successful formula because parenthood is inherently unpredictable and so is your work."

The most intriguing question is whether Clijsters's experiences as a mother made her more likely to win. Could a broader focus have been a help? On days off, the player would take her daughter on carriage trips around Central Park rather than knocking balls around the practice courts. Both Bishop and Thompson talk of being better at focusing since having their children.

It is a possibility that appeared to intrigue Serena Williams, pondering on her rival. "Seems like she's even faster than what she was before. I was thinking that maybe I should have a baby and then I'll come back faster."

Going back to work

Cherie Booth QC went back to work only weeks after her son Leo was born in 2000. With an eight-week-old baby and three teenagers, trying to juggle family life with her career was like walking on a "tightrope", she said.

Catherine Zeta-Jones capped a remarkable rise in Hollywood, winning best supporting actress for her role in the film version of the stage hit Chicago in 2003, soon after the birth of her first child, Dylan. "I knew I couldn't be superwoman, so hey-ho, I don't get to put Dylan to bed a few nights. That doesn't make me a bad mother. You have to juggle," she said.

Marathon runner Paula Radcliffe, left, was still racing while six months pregnant. She resumed her career by storming to victory in the 2007 New York marathon, 10 months after the birth of her daughter, Isla. Paula Radcliffe now has her sights set on Olympic glory at the 2012 London Olympics.

Catriona Matthew became the first Scottish woman to clinch a major golf title earlier this year when she won the Women's British Open. She had given birth to her second child 11 weeks earlier.

Business titan Nicola Horlick, 48, has had six children and confounded her doubters in the City by quickly returning to work each time. In 2004 she proved she still had the golden touch by setting up consultancy group, Bramdean Asset Management.

Rachida Dati, the former French justice minister, returned to work in January, five days after giving birth to a girl. by caesarean section. Photographs of her rushing back to the ministry were flashed around the world. She told a French newspaper: "You mustn't believe I wasn't tired," she said.